Many methods have been devised to generate steam and many are working even today. Most of these steam generators are bulky, complicated, and are not easily portable due to the water reservoir, boilers and pressure vessels involved etc while the efficiency of the systems is also low as most of the stored water has to be continuously boiled or heated and kept hot throughout the evaporation process.
U.S. Pat. No. 4,801,424 B2 Dated Feb. 20, 2007 discloses a steam generator comprising a heating unit, pump adapted to deliver a controllable flow of water from a water supply into the heating unit and an outlet for steam from the heating unit. The unit comprising of a housing, a heating element disposed in the housing and a conduit for water and steam extending from the inlet to the outlet; the conduit including a passage way extending in an elongated path in contact with or adjacent the heating element; wherein the housing comprises two portions releasably secured together to provide a channel between the portions to receive the heating element and to further provide the passageway.
The surface area that can be heated is limited and the evaporation efficiency is less. Steam generators with submerged electric resistors have draw backs of higher start up times running to about 10 minutes and have an added problem of overheating in absence of water and scaling. Dragging of water drops is an occasional problem due to existence of boiling.
WIPO patent application WO/2010/119405 A2 published Oct. 21, 2010 discloses an electric steam generator heating element for heating water to be evaporated, consisting of an electric resistor inserted in a profiled base of a support, fixed in a hole obtained in one of the vertical walls of the container for heating water. Though this device claims many improvements, it still has many limitations like submerged heating element. Limited contact area, complicated manufacturing procedure.
U.S. Pat. No. 5,063,609 discloses a steam generator comprising, a plurality of stacked, interconnected, vertically-oriented liquid-holding chambers, there being a top chamber and a bottom chamber, each chamber having means for heating the water in each chamber to create steam in each of said chambers, with heating means immersed in liquid in each chamber. Here the steam produces from a lower chamber to the chambers above is transferred prior to releasing said steam from the collection zone. Though this device claims efficiency, the bulk of the water is heated and thereby reducing its efficiency.
In US Patent Application 20050178761 A1 relates to a superheated vapor generator having a tubular, vertically extending container with high frequency induction heating coil wound around the container. A heating medium which is heatable by electromagnetic conduction is placed in the container. A number of vapor passages extend through the heating medium longitudinally of the tubular container. The tubular container has a heating section with the heating coil and a non-heating section under the heating section. Material for superheated vapor is supplied through a supply passage from a position above the heating medium to the non-heating section. A passage structure is provided in the non-heating section for flow of material supplied through the supply passage there through into the vapor passages of the heating medium. A discharge passage is formed above the heating medium. A discharge passage is formed above the heating medium for discharging superheated vapour. It can be seen that the device still has to depend on heating the bulk of water first and then evaporate to and superheat resulting in poor efficiency.
In U.S. Pat. No. 4,724,824 dated 16 Feb. 1988, an instantaneous steam generator is disclosed which has a plurality of heated channels having open tops. Each channel has a base having a steam generation surface with substantially parallel, sharp transverse ridges. The steam generation surface is heated to a temperature substantially above that at which an insulating vapor barrier forms between the surface and a water layer there above. The water flow is directed transversely over the ridges so that the vapor layer is separated from the water layer above and so that the water is instantaneously converted into steam rather than riding on an insulating layer of water vapor. The channels can be enclosed in a box having openings. The box is pressurized by a blower drawing relatively cool, ambient air so that relatively wet steam is distributed throughout the entire interior volume of a large oven. Control apparatus for heating the channels and controlling the water flow thereto are described. The instantaneous steam generation has a short regeneration period which allows re-steaming of an oven during a baking cycle however it is a very complicated unit and lacking in ease of manufacture. Also efficiency of evaporation is low.
US patent application 20110274416 A1 dated Jul. 9, 2010 disclosing a steam generator includes a body defining therein a flow passage having an inlet and an outlet, a heater installed in the body and adapted for heating water being guided through the inlet of the flow passage into the inside of the flow passage into steam for enabling steam generation to flow out of the outlet of the flow passage, and at least one friction unit mounted in the flow passage and movable by generated steam to rub against the inside wall of the flow passage and to remove water scale from the inside wall. Thus, the steam generator uses the friction unit to remove water scale from the inside wall of the flow passage during operation, avoiding water scale accumulation and prolonging the lifespan. Though inefficient in energy utilization, the device may operate for large scale operations. But on a small scale, the manufacture may be more cumbersome.
Hence scope exists to simplify the system to provide a very efficient, compact, portable and economical steam generator
Summing up, the prior art disclosures suffer from the following often observed limitations                1) Construction requires high pressure pumps, pressure vessels, seamless pipe lines and insulated body in addition to being, expensive to construct.        2) The heating electrode is submerged in water resulting in scaling on heater and severe bubbling resulting in droplets of water in steam and also early heater failure        3) Very limited contact surface area for efficient evaporation to take place        4) Water stored for evaporation is heated continuously.        5) Poor energy utilization        6) Rigorous safety standards to be followed.        
To overcome the above deficiencies, I have come out with an electrically operated low pressure steam generator which ensures maximum energy efficiency, minimum or low operating pressure, increased safety, adaptability to different process, simplicity in construction and, easiness in control on the parameters.
The problems of the existing known conventional steam generators can be solved by the present invention.
Increased interest in using steam for cleaning as a replacement of Chemicals in this enviro-conscious industry, using steam for warming food and for sterilizing objects or spaces, and superheated steam for drying, curing, beauty salons and Spa, and special applications like high purity water production, electronic chip cleaning etc, has made it necessary to generate more steam with less power in a safe environment. The electrical steam generator of the present invention offers a simplified pressure less superheated steam generation unit which can also function as a batch type unit when so desired. This device of the present invention is useful in many ways in different applications like, steam cleaning, humidification of an enclosed space, sterilization, mushroom farming, incubators, green houses, heating curing applications, other industrial needs, pure water generation etc.
A simple, electrical low pressure high temperature steam generator with limited components, will not only help in increased safety of operation, but also reduce the size, and weight, simplify the construction, thereby reduce manufacturing cost, while increasing the efficiency. Hence it is very important to have a steam generator which is simple in construction with less number of components wherein,                The steam generator does not require high pressure boilers and accessories to generate high temperature steam        The steam generator would be compact in size        Then steam generator will be easy to assemble and dissemble        The steam generator need not have too much of metallic components in and around the heat source.        High energy efficiency        The surface area of the steam generating body is considerably high while its heat mass is low.        Steam can be made to pass through a moist body within the system itself thereby increasing its wetness where required.        The steam generator does not waste heat to preheat any stored water.        The water reaching the hot zone is necessarily evaporated.        The steam generator is very safe even while generating super heated steam        The steam generator is very easily portable.        The steam generator leaves behind a very small foot print.Such a device would be of immense help to science and technology and to the industry on the whole.        
Therefore the main object of the present invention is to provide a large evaporating surface area in a small volume by means of a porous ceramic body absorbing water to increase the steam generating efficiency of the device,
Another objective of the present invention is to produce super heated steam while totally avoiding usage of high pressure boilers, high pressure pumps, valves, pressure gauges etc and complicated operations.
Another objective of the present invention is to ensure that bulk movement and bulk heating of water is totally avoided
Another objective of the present invention is to provide a porous body ceramic honeycomb made of alumina, cordierite, clay, and steatite, and zirconia, mullite as the medium to absorb and hold water in a very fine dispersion
Yet another objective of the present invention is to employ thin walled ceramic honeycomb in one piece or more number of pieces stacked in a predetermined manner with all channels parallel to one another while the channel cross section is square or rectangular or hexagonal or triangular or round etc
Yet another object of the present invention is to employ any porous water absorbing ceramic body to increase the area of water dispersion and thus increase the steam generating area and employ it as a means to generate steam in the steam generator of the present invention.
Another object of the present invention is to have one or more electrical resistance heating electrodes in the form of electrical resistant wire, strip, rod in a straight line, zig zag or coiled fashion or tube heaters to provide the required heat for evaporation.
Yet another objective of the present invention is to provide means for steam to pass through a moist medium to produce low temperature wet steam where ever required.
Yet another objective of the present invention is to ensure that the entire electrical energy input is almost instantly converted to steam energy and there is a minimum heat mass in the steam generating body.
Yet another objective is to avoid or minimize pre-heating of whatever little free water body there is in the steam generator.
The above mentioned objectives of the present invention have been achieved based on my findings that the porous ceramic honeycomb monolith absorbs water and the pores present in the body behave like a bunch of capillary tubes network and suck up maximum quantities of water along its channel walls when the axis of the honeycomb channels are vertically oriented. The present invention allows installing of heating element in horizontally aligned spaces created by drilling or digging out required portions from the ceramic honeycomb monolith.